Booster pump vapor separator



Dec. 22, 1942. R. R. cum-1s 2,306,299

BOOSTER PUMP VAPOR SEPARATOR Filed Oct. 18, 1941 I "II Ir I 2 3' V g 5 fiver-22:1

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Patented Dec. 22, 1942 UNITED STATES PATENT OFFICE BOOSTER PUMP VAPOR SEPARATOR Russell R. Curtis, Dayton, Ohio, assignor to Curtis Pump Company, Dayton, Ohio, :1. corporation of Ohio Application October 18, 1941, Serial No. 415,516

6 Claims.

shaped guides for directing the liquid to bev pumped to the agitators and for directing the separated gases and vapors away from the pump.

This application is a continuation in part of my copending application entitled: Booster pump, Serial No. 409,647, filed September 5, 1941.

In accordance with this invention a pump casing is so mounted with relation to a source of liquid such as a fuel tankas to be below the hydraulic gradient of the liquid. The casing has an inlet throat communicating with the source of liquid and a volute chamber receiving pressured liquid from the throat. An impeller disk having pumping vanes thereon centrifugally pumps the liquid from the throat to the volute chamber. This impeller assembly also carries an agitating propeller in spaced relation from the pumping vane and preferably at the inlet to the throat. A guide or shield is mounted in spaced relation from the inlet throat to direct liquid to the agitating propeller along a converging path. This path converges at a relatively high rate to a point spaced from the discharge end thereof and then converges from this point at a slower rate to the discharge end thereof. The resulting bell mouthed path has very high fluid flow capacity.

The agitating propeller effects the formation of bubbles from gas and vapor in the liquid and creates a radial flow of liquid which carries the bubbles radially outward through the space between the guide or shield and the inlet throat member.

In addition, the propeller raises the pressure in the area between the propeller and impeller and starts the liquid to whirl so that when the liquid strikes the open edges of the impeller vanes, only a negligible amount of vaporization can take place.

The outer face of the shield directs bubbles of gas and vapor from the agitating propeller out of the path of the incoming liquid so that the bubbles are not entrained in the liquid entering the pump. At the same time the liquid is delivered to the agitating propeller at a minimum pressure so that bubble formation at the propeller is enhanced.

A feature of the invention also includes the provision of a continually converging liquid flow path in the pump from the agitating propeller through the inlet throat and into the volute chamber.

It is, then, an object of this invention to provide improved guide shields for the inlet of pumps.

Another object of the invention is to provide centrifugal pumps with bell mouth shaped guide SillGldS for directing liquid to the inlet thereof.

A specific object of the invention is to provide fuel pumps with fuel directing shield means designed to enhance the capacity of the pump.

A specific object of the invention is to provide a booster pump having an agitating propeller lying above the mouth thereof with a bell mouth shaped annular fluid guide shield which discharges fluid to the agitating propeller and which guides gas and vapor bubbles from the impeller away from the pump inlet.

A further specific object of the invention is to increase the pumping capacity of centrifugal booster pumps by the use of bell mouth shaped annular guide shields which direct fluid to the pump.

Other and further objects of the invention will be apparent to those skilled in theart from the following detailed description of the annexed sheet of drawings which, by way of preferred examples illustrate two embodiments of the invention.

0n the drawing:

Figure 1 is a vertical cross-sectional view, partly in elevation, and with parts broken away, of a booster pump, guide shield, and fuel tank assembly in accordance with this invention.

Figure 2 is a plan view of the booster pump and guide shield assembly shown in Figure 1 viewed along the line IIII of Figure 1.

Figure 3 is an enlarged fragmentary vertical cross-sectional view of the booster pump and guide shield assembly shown in Figures 1 and 2 and better illustrating the curvature of the guide shield.

Figure 4 is a vertical cross-sectional view oi a modified booster pump and guide shield "assembly according to this invention.

As shown on the drawing:

In Figure l the reference numeral Ill designates a'fuel tank, vented as at Illa, and con-' taining a pond P of liquid fuel such as gasoline. The bottom wall of the tank has a circular aperber l5, a discharge outlet 18 for ture lob therein and a mounting ring I2 is mounted in the tank on the bottom wall around the aperture.

The booster pump I3 is of the centrifugal type and includes a casing l4 defining a volute chamthe volute chamber, and a shaft housing ll. The casing I4 is connected with an electric motor (not shown) which drives the shaft l8 in the shaft housing portion ll of the casing. The casing has an outtumed annular flange l8 for mounting on the bottom wall of the tank. The flange l3 receives screws 28 at spaced intervals therearound which are threaded into blind tapped wells in the mounting ring I2. The mounting ring may be welded, soldered, or otherwise secured to the bottom wall of the tank.

The casing defines a circular opening 2| into which a throat ring 22 is seated. The throat ring 22 partially overlies the flange l9. Bolts 23, at spaced intervals around the throat ring, are threaded through the ring into the flange portion Hi to mount the ring on the casing 14.

The throat ring 22 has a central aperture 24 therethrough for joining the interior of the tank II with the volute chamber I5. The aperture 24 flares outwardly as at 24a to provide an inlet mouth for the booster pump.

A plurality of standards or ribs 25, each having a foot portion 25a, are disposed around the throat ring and secured thereon by the bolts 23 which extend through the feet portions 25a.

The standards or ribs 25 are fixedly secured at their upper ends to a bell mouth annular shield 26. The ribs 25 carry the shield 26 in spaced relation above the throat ring 22.

The shield 25 has an inner face 26a which, as best shown in Figure 3, converges from the upper end of. the shield at a relatively high rate to a point intermediate the top and bottom of the shield. The face then converges at a slower rate from this point to the bottom or-discharge end of the shield. The inner face 26a has a smooth continuous curvature especially designed for high fluid flow capacity *gwithout, however, requiring undue head or pressure. This particular curvature has greatly enhanced the pumping capacity of the booster pump since it flares outwardly at the inlet end thereof to receive fuel from the pond P over a relatively large area and then guides the fuel inwardly from this large area along a path having a relatively small vertical component to a point ahead of the discharge mouth of the shield. While the path continues to converge from this point it converges at a slower rate and thus does not materially-increase the head or pressure required to produce any given velocity. The reduced height of the shield positions the inlet end thereof closer to the bottom of the tank so that the fuel even at lowlevels in the tank will enter the guide.

The booster pump has an impeller assembly 21 mounted on the drive shaft 18. This impeller assembly includes a disk or flange portion 28 spanning the inlet or aperture 24 in the throat ring and communicating freely around the periphery thereof with the inner rim of the volute chamber I5. Curved pumping vanes 29 are mounted on the flange 28 around the periphery thereof to underlie the throat ring 22. These pumping vanes 28 define, with the throat ring 22 and the flange 28, open ended pumping chan-.

nels communicating at their outer ends with the volute chamber I and at their inner ends with the inlet of the throat ring.

A cap member 38 is threaded onto the shaft portion 18 extending above the impeller disk 28. This cap has a threaded extension 38a on the top thereof receiving therearound a propeller 3| with four blades 3|a radiating. therefrom. A nut 32 is threaded on the portion 38a of the cap to hold the propeller 3| in position.

The blades 3la of the propeller are disposed in the space between the bottom of the shield 25 and the top of the throat ring 22. As best shown in Figure 2, the blades 3la extend across the entire discharge mouth of the shield 28.

As best shown in Figure 1, the propeller blades 3la agitate the fuel flowing down through the shield 26 as soon as the fuel'is discharged from the shield. The propeller beats out bubbles B of gases and vapors from the liquid fuel and throws these bubbles outwardly from the discharge mouth of the shield where they can rise in the pond P along a path between the shield and throat ring. The outer face 26b of the shield slopes upwardly and outwardly away from the throat ring so that the bubbles are guided away from the inlet to the shield. The bubble path, as shown in Figure l, widens out and the bubbles become larger as they approach the surface of the pond P. Upon reaching the surface of the pond the bubbles burst intothe atmosphere and discharge their vapors or gases.

It should therefore be understood that the shield 25 serves two functions, namely, to increase the feed of liquid fuel to the pump and to guide the beaten out bubbles away from the incoming liquid fuel. The curvature of the inner face of the shield is designed so that the shield can be relatively flat, receive liquid from a large area, and discharge it out of a smaller area at minimum pressure, so as not to interfere with the bubble separation.

The bubble-freed liquid enters the pump through the inlet mouth 24 of the throat ring. It is pressured by the impeller assembly into the volute chamber.

In the modification shown in Figure 4, parts identical with parts described in Figures 1 to 3 have been marked with the same reference numerals. In Figure 4 the throat ring 22 has a modified inlet mouth 24a which converges inwardly from the top thereof and then has a rounded bottom 24b flaring outwardly into the volute chamber IS. The pumping vanes 28:: on the impeller disk 28 have upper edges curved to conform with the curvature 24b.

The cap member 38 is filleted as at 35 with metal or plastic material to define a surface 35a sweeping outwardly from the upper end of the cap with the same curvature as the throat ring aperture. As a result of this construction a constantly converging path for the liquid flowing through the inlet throat of the pump is provided from the very top of the inlet to the volute chamber. This constantly converging path sweeps inwardly to the central portion of the throat ring and thence outwardly into the volute chamber. The constant convergence prevents bubble generation in the pump and aids the vanes 28a. in pressuring the fuel. A smoother fuel flow is obtained and the pumping capacity is further enhanced by elimination of all pockets or fluid traps.

It will,'of course, be understood that various details of construction may be varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

1. In a pump construction including a pump casing having an inlet throat, an impeller with pumping vanes underlapping the throat, and agitating vanes positioned to act on material fed to the pump before the material reaches the pumping vanes, the improvement which comprises a guide shield mounted in advance of the throat and the agitating vanes defining an annular bell mouthed passage to the throat in localized transverse communication with the exterior of the shield.

2. In a pump construction including a pump casing having an inlet throat, an impeller with pumping vanes underlapping the throat, and agitating vanes positioned to act on liquid fed to the pump before the liquid reaches the pumping vanes, the improvement of a guide shield mounted in advance of the throat and the agitating vanes in spaced relation therefrom and having an annular inner face converging along a curved path and changing in rate of curvature as it approaches the agitating vanes.

-3. In a booster pump assembly including an inlet throat, an impeller having pumping vanes underlapping the throat, and an agitating propeller in advance of the throat, the improvement of standards mounted on the throat and a relatively shallow annular shield carried by said standards defining a localized flow path to the propeller and the pumping vanes through the inlet throat, said shield terminating in spacedrelation from the throat and the pumping vanes to cooperate therewith for defining a path isolated from the localized feed path for bubbles generated by the agitating propeller.

4. A booster pump construction comprising a casing defining an annular volute chamber, an impeller mounted centrally of said vol ute chamber and extending into the chamber around the periphery thereof, a throat ring having an aperture therethrough flaring outwardly into the volute chamber, a guide shield in advance of a spaced from said throat ring for defining a flow path to the throat ring aperture, an agit ating propeller in said flow path between said throat ring and said guide shield arranged for free transverse communication with a body of liquid surrounding the flow path, pumping vanes around the periphery of the impeller and underlying the throat ring and having continguous edge portions of the same curvature as the throat ring, and

means defining a surface on the impeller extending into said aperture in spaced relation from the throat ring for cooperating with the aperture curvature to define an outwardly flaring converging annular path into the volute chamber.

5. A booster pump construction comprising a pump casing defining an annular volute chamber, a throat ri'ng mounted on said casing defining an inlet to said volute chamber and having an outwardly flaring inlet mouth, an impeller disk mounted in said casing and spanning said inlet mouth, pumping vanes on the periphery of said impeller underlying said'throat ring, a propeller mounting on said impeller extending through said throat ring, a propeller on said mounting in advance of the outwardly flaring inlet mouth ofthe throat ring, and a relatively shallow annular shield mounted on said throat ring in spaced relation from the inlet mouth thereof defining a I curved localized flow path to the propeller.

6. A booster pump construction comprising a pump having an inlet mouth, a volute chamber in communication with said mouth, an impeller for centrifugally discharging liquid from the inlet mouth into the volute chamber, a propeller mounted on said impeller in advance of the inlet mouth, and an annular imperforate shield in advance of said propeller having a smooth curved inner face converging at a non-uniform rate toward said propeller to define a liquid fuel path to the propeller, said shield cooperating with said inlet mouth of the pump to define a space therebetween adjacent the propeller for joining the liquid flow path with the outside of the shield, and said shield having an outer face sloping away from said propeller to guide bubbles thrown from space away from the RUSSELL R. CURTIS.

incoming liquid. 

